
if(NOT ADDRESS_MODEL)
    if (CMAKE_SIZEOF_VOID_P MATCHES "8")
        set( ADDRESS_MODEL "64" )
        message(STATUS "model 64" )
    elseif(CMAKE_SIZEOF_VOID_P MATCHES "4")
        set( ADDRESS_MODEL "32" )
        message(STATUS "model 32" )
    else()
        message(FATAL_ERROR "unkown address model" )
    endif()
endif()







